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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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![Matthias Maennich](/assets/img/avatar_default.png)
[ Upstream commit a979522a1a
]
To avoid unnecessary recompilations, mkcompile_h does not regenerate
compile.h if just the timestamp changed.
Though, if KBUILD_BUILD_TIMESTAMP is set, an explicit timestamp for the
build was requested, in which case we should not ignore it.
If a user follows the documentation for reproducible builds [1] and
defines KBUILD_BUILD_TIMESTAMP as the git commit timestamp, a clean
build will have the correct timestamp. A subsequent cherry-pick (or
amend) changes the commit timestamp and if an incremental build is done
with a different KBUILD_BUILD_TIMESTAMP now, that new value is not taken
into consideration. But it should for reproducibility.
Hence, whenever KBUILD_BUILD_TIMESTAMP is explicitly set, do not ignore
UTS_VERSION when making a decision about whether the regenerated version
of compile.h should be moved into place.
[1] https://www.kernel.org/doc/html/latest/kbuild/reproducible-builds.html
Signed-off-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
109 lines
2.8 KiB
Bash
Executable file
109 lines
2.8 KiB
Bash
Executable file
#!/bin/sh
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# SPDX-License-Identifier: GPL-2.0
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TARGET=$1
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ARCH=$2
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SMP=$3
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PREEMPT=$4
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CC=$5
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vecho() { [ "${quiet}" = "silent_" ] || echo "$@" ; }
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# If compile.h exists already and we don't own autoconf.h
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# (i.e. we're not the same user who did make *config), don't
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# modify compile.h
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# So "sudo make install" won't change the "compiled by <user>"
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# do "compiled by root"
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if [ -r $TARGET -a ! -O include/generated/autoconf.h ]; then
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vecho " SKIPPED $TARGET"
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exit 0
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fi
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# Do not expand names
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set -f
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# Fix the language to get consistent output
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LC_ALL=C
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export LC_ALL
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if [ -z "$KBUILD_BUILD_VERSION" ]; then
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if [ -r .version ]; then
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VERSION=`cat .version`
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else
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VERSION=0
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echo 0 > .version
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fi
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else
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VERSION=$KBUILD_BUILD_VERSION
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fi
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if [ -z "$KBUILD_BUILD_TIMESTAMP" ]; then
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TIMESTAMP=`date`
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else
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TIMESTAMP=$KBUILD_BUILD_TIMESTAMP
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fi
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if test -z "$KBUILD_BUILD_USER"; then
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LINUX_COMPILE_BY=$(whoami | sed 's/\\/\\\\/')
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else
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LINUX_COMPILE_BY=$KBUILD_BUILD_USER
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fi
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if test -z "$KBUILD_BUILD_HOST"; then
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LINUX_COMPILE_HOST=`hostname`
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else
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LINUX_COMPILE_HOST=$KBUILD_BUILD_HOST
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fi
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UTS_VERSION="#$VERSION"
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CONFIG_FLAGS=""
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if [ -n "$SMP" ] ; then CONFIG_FLAGS="SMP"; fi
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if [ -n "$PREEMPT" ] ; then CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT"; fi
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UTS_VERSION="$UTS_VERSION $CONFIG_FLAGS $TIMESTAMP"
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# Truncate to maximum length
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UTS_LEN=64
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UTS_TRUNCATE="cut -b -$UTS_LEN"
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# Generate a temporary compile.h
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( echo /\* This file is auto generated, version $VERSION \*/
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if [ -n "$CONFIG_FLAGS" ] ; then echo "/* $CONFIG_FLAGS */"; fi
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echo \#define UTS_MACHINE \"$ARCH\"
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echo \#define UTS_VERSION \"`echo $UTS_VERSION | $UTS_TRUNCATE`\"
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echo \#define LINUX_COMPILE_BY \"`echo $LINUX_COMPILE_BY | $UTS_TRUNCATE`\"
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echo \#define LINUX_COMPILE_HOST \"`echo $LINUX_COMPILE_HOST | $UTS_TRUNCATE`\"
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echo \#define LINUX_COMPILER \"`$CC -v 2>&1 | grep ' version ' | sed 's/[[:space:]]*$//'`\"
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) > .tmpcompile
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# Only replace the real compile.h if the new one is different,
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# in order to preserve the timestamp and avoid unnecessary
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# recompilations.
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# We don't consider the file changed if only the date/time changed,
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# unless KBUILD_BUILD_TIMESTAMP was explicitly set (e.g. for
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# reproducible builds with that value referring to a commit timestamp).
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# A kernel config change will increase the generation number, thus
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# causing compile.h to be updated (including date/time) due to the
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# changed comment in the
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# first line.
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if [ -z "$KBUILD_BUILD_TIMESTAMP" ]; then
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IGNORE_PATTERN="UTS_VERSION"
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else
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IGNORE_PATTERN="NOT_A_PATTERN_TO_BE_MATCHED"
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fi
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if [ -r $TARGET ] && \
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grep -v $IGNORE_PATTERN $TARGET > .tmpver.1 && \
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grep -v $IGNORE_PATTERN .tmpcompile > .tmpver.2 && \
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cmp -s .tmpver.1 .tmpver.2; then
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rm -f .tmpcompile
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else
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vecho " UPD $TARGET"
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mv -f .tmpcompile $TARGET
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fi
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rm -f .tmpver.1 .tmpver.2
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